1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Support for dynamic device trees.
   4 *
   5 * On some platforms, the device tree can be manipulated at runtime.
   6 * The routines in this section support adding, removing and changing
   7 * device tree nodes.
   8 */
   9
  10#define pr_fmt(fmt)	"OF: " fmt
  11
  12#include <linux/cleanup.h>
  13#include <linux/device.h>
  14#include <linux/of.h>
  15#include <linux/spinlock.h>
  16#include <linux/slab.h>
  17#include <linux/string.h>
  18#include <linux/proc_fs.h>
  19
  20#include "of_private.h"
  21
  22static struct device_node *kobj_to_device_node(struct kobject *kobj)
  23{
  24	return container_of(kobj, struct device_node, kobj);
  25}
  26
  27/**
  28 * of_node_get() - Increment refcount of a node
  29 * @node:	Node to inc refcount, NULL is supported to simplify writing of
  30 *		callers
  31 *
  32 * Return: The node with refcount incremented.
  33 */
  34struct device_node *of_node_get(struct device_node *node)
  35{
  36	if (node)
  37		kobject_get(&node->kobj);
  38	return node;
  39}
  40EXPORT_SYMBOL(of_node_get);
  41
  42/**
  43 * of_node_put() - Decrement refcount of a node
  44 * @node:	Node to dec refcount, NULL is supported to simplify writing of
  45 *		callers
  46 */
  47void of_node_put(struct device_node *node)
  48{
  49	if (node)
  50		kobject_put(&node->kobj);
  51}
  52EXPORT_SYMBOL(of_node_put);
  53
  54static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
  55
  56int of_reconfig_notifier_register(struct notifier_block *nb)
  57{
  58	return blocking_notifier_chain_register(&of_reconfig_chain, nb);
  59}
  60EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
  61
  62int of_reconfig_notifier_unregister(struct notifier_block *nb)
  63{
  64	return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
  65}
  66EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
  67
  68static const char *action_names[] = {
  69	[0] = "INVALID",
  70	[OF_RECONFIG_ATTACH_NODE] = "ATTACH_NODE",
  71	[OF_RECONFIG_DETACH_NODE] = "DETACH_NODE",
  72	[OF_RECONFIG_ADD_PROPERTY] = "ADD_PROPERTY",
  73	[OF_RECONFIG_REMOVE_PROPERTY] = "REMOVE_PROPERTY",
  74	[OF_RECONFIG_UPDATE_PROPERTY] = "UPDATE_PROPERTY",
  75};
  76
  77#define _do_print(func, prefix, action, node, prop, ...) ({	\
  78	func("changeset: " prefix "%-15s %pOF%s%s\n",		\
  79	     ##__VA_ARGS__, action_names[action], node,		\
  80	     prop ? ":" : "", prop ? prop->name : "");		\
  81})
  82#define of_changeset_action_err(...) _do_print(pr_err, __VA_ARGS__)
  83#define of_changeset_action_debug(...) _do_print(pr_debug, __VA_ARGS__)
  84
  85int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
  86{
  87	int rc;
 
  88	struct of_reconfig_data *pr = p;
  89
  90	of_changeset_action_debug("notify: ", action, pr->dn, pr->prop);
 
 
 
 
 
 
 
 
 
 
 
  91
 
 
  92	rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
  93	return notifier_to_errno(rc);
  94}
  95
  96/*
  97 * of_reconfig_get_state_change()	- Returns new state of device
  98 * @action	- action of the of notifier
  99 * @arg		- argument of the of notifier
 100 *
 101 * Returns the new state of a device based on the notifier used.
 102 *
 103 * Return: OF_RECONFIG_CHANGE_REMOVE on device going from enabled to
 104 * disabled, OF_RECONFIG_CHANGE_ADD on device going from disabled to
 105 * enabled and OF_RECONFIG_NO_CHANGE on no change.
 106 */
 107int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
 108{
 109	struct property *prop, *old_prop = NULL;
 110	int is_status, status_state, old_status_state, prev_state, new_state;
 111
 112	/* figure out if a device should be created or destroyed */
 113	switch (action) {
 114	case OF_RECONFIG_ATTACH_NODE:
 115	case OF_RECONFIG_DETACH_NODE:
 116		prop = of_find_property(pr->dn, "status", NULL);
 117		break;
 118	case OF_RECONFIG_ADD_PROPERTY:
 119	case OF_RECONFIG_REMOVE_PROPERTY:
 120		prop = pr->prop;
 121		break;
 122	case OF_RECONFIG_UPDATE_PROPERTY:
 123		prop = pr->prop;
 124		old_prop = pr->old_prop;
 125		break;
 126	default:
 127		return OF_RECONFIG_NO_CHANGE;
 128	}
 129
 130	is_status = 0;
 131	status_state = -1;
 132	old_status_state = -1;
 133	prev_state = -1;
 134	new_state = -1;
 135
 136	if (prop && !strcmp(prop->name, "status")) {
 137		is_status = 1;
 138		status_state = !strcmp(prop->value, "okay") ||
 139			       !strcmp(prop->value, "ok");
 140		if (old_prop)
 141			old_status_state = !strcmp(old_prop->value, "okay") ||
 142					   !strcmp(old_prop->value, "ok");
 143	}
 144
 145	switch (action) {
 146	case OF_RECONFIG_ATTACH_NODE:
 147		prev_state = 0;
 148		/* -1 & 0 status either missing or okay */
 149		new_state = status_state != 0;
 150		break;
 151	case OF_RECONFIG_DETACH_NODE:
 152		/* -1 & 0 status either missing or okay */
 153		prev_state = status_state != 0;
 154		new_state = 0;
 155		break;
 156	case OF_RECONFIG_ADD_PROPERTY:
 157		if (is_status) {
 158			/* no status property -> enabled (legacy) */
 159			prev_state = 1;
 160			new_state = status_state;
 161		}
 162		break;
 163	case OF_RECONFIG_REMOVE_PROPERTY:
 164		if (is_status) {
 165			prev_state = status_state;
 166			/* no status property -> enabled (legacy) */
 167			new_state = 1;
 168		}
 169		break;
 170	case OF_RECONFIG_UPDATE_PROPERTY:
 171		if (is_status) {
 172			prev_state = old_status_state != 0;
 173			new_state = status_state != 0;
 174		}
 175		break;
 176	}
 177
 178	if (prev_state == new_state)
 179		return OF_RECONFIG_NO_CHANGE;
 180
 181	return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
 182}
 183EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
 184
 185int of_property_notify(int action, struct device_node *np,
 186		       struct property *prop, struct property *oldprop)
 187{
 188	struct of_reconfig_data pr;
 189
 190	/* only call notifiers if the node is attached */
 191	if (!of_node_is_attached(np))
 192		return 0;
 193
 194	pr.dn = np;
 195	pr.prop = prop;
 196	pr.old_prop = oldprop;
 197	return of_reconfig_notify(action, &pr);
 198}
 199
 200static void __of_attach_node(struct device_node *np)
 201{
 202	const __be32 *phandle;
 203	int sz;
 204	unsigned long flags;
 205
 206	raw_spin_lock_irqsave(&devtree_lock, flags);
 
 207
 208	if (!of_node_check_flag(np, OF_OVERLAY)) {
 209		np->name = __of_get_property(np, "name", NULL);
 210		if (!np->name)
 211			np->name = "<NULL>";
 212
 213		phandle = __of_get_property(np, "phandle", &sz);
 214		if (!phandle)
 215			phandle = __of_get_property(np, "linux,phandle", &sz);
 216		if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
 217			phandle = __of_get_property(np, "ibm,phandle", &sz);
 218		if (phandle && (sz >= 4))
 219			np->phandle = be32_to_cpup(phandle);
 220		else
 221			np->phandle = 0;
 222	}
 223
 224	np->child = NULL;
 225	np->sibling = np->parent->child;
 226	np->parent->child = np;
 227	of_node_clear_flag(np, OF_DETACHED);
 228	np->fwnode.flags |= FWNODE_FLAG_NOT_DEVICE;
 229
 230	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 231
 232	__of_attach_node_sysfs(np);
 233}
 234
 235/**
 236 * of_attach_node() - Plug a device node into the tree and global list.
 237 * @np:		Pointer to the caller's Device Node
 238 */
 239int of_attach_node(struct device_node *np)
 240{
 241	struct of_reconfig_data rd;
 
 242
 243	memset(&rd, 0, sizeof(rd));
 244	rd.dn = np;
 245
 246	mutex_lock(&of_mutex);
 
 247	__of_attach_node(np);
 
 
 
 248	mutex_unlock(&of_mutex);
 249
 250	of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
 251
 252	return 0;
 253}
 254
 255void __of_detach_node(struct device_node *np)
 256{
 257	struct device_node *parent;
 258	unsigned long flags;
 259
 260	raw_spin_lock_irqsave(&devtree_lock, flags);
 
 261
 262	parent = np->parent;
 263	if (WARN_ON(of_node_check_flag(np, OF_DETACHED) || !parent)) {
 264		raw_spin_unlock_irqrestore(&devtree_lock, flags);
 265		return;
 266	}
 267
 268	if (parent->child == np)
 269		parent->child = np->sibling;
 270	else {
 271		struct device_node *prevsib;
 272		for (prevsib = np->parent->child;
 273		     prevsib->sibling != np;
 274		     prevsib = prevsib->sibling)
 275			;
 276		prevsib->sibling = np->sibling;
 277	}
 278
 279	of_node_set_flag(np, OF_DETACHED);
 280
 281	/* race with of_find_node_by_phandle() prevented by devtree_lock */
 282	__of_phandle_cache_inv_entry(np->phandle);
 283
 284	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 285
 286	__of_detach_node_sysfs(np);
 287}
 288
 289/**
 290 * of_detach_node() - "Unplug" a node from the device tree.
 291 * @np:		Pointer to the caller's Device Node
 
 
 292 */
 293int of_detach_node(struct device_node *np)
 294{
 295	struct of_reconfig_data rd;
 
 
 296
 297	memset(&rd, 0, sizeof(rd));
 298	rd.dn = np;
 299
 300	mutex_lock(&of_mutex);
 
 301	__of_detach_node(np);
 
 
 
 302	mutex_unlock(&of_mutex);
 303
 304	of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
 305
 306	return 0;
 307}
 308EXPORT_SYMBOL_GPL(of_detach_node);
 309
 310void __of_prop_free(struct property *prop)
 311{
 312	kfree(prop->name);
 313	kfree(prop->value);
 314	kfree(prop);
 315}
 316
 317static void property_list_free(struct property *prop_list)
 318{
 319	struct property *prop, *next;
 320
 321	for (prop = prop_list; prop != NULL; prop = next) {
 322		next = prop->next;
 323		__of_prop_free(prop);
 
 
 324	}
 325}
 326
 327/**
 328 * of_node_release() - release a dynamically allocated node
 329 * @kobj: kernel object of the node to be released
 330 *
 331 * In of_node_put() this function is passed to kref_put() as the destructor.
 332 */
 333void of_node_release(struct kobject *kobj)
 334{
 335	struct device_node *node = kobj_to_device_node(kobj);
 336
 337	/*
 338	 * can not use '"%pOF", node' in pr_err() calls from this function
 339	 * because an of_node_get(node) when refcount is already zero
 340	 * will result in an error and a stack dump
 341	 */
 342
 343	/* We should never be releasing nodes that haven't been detached. */
 344	if (!of_node_check_flag(node, OF_DETACHED)) {
 345
 346		pr_err("ERROR: %s() detected bad of_node_put() on %pOF/%s\n",
 347			__func__, node->parent, node->full_name);
 348
 349		/*
 350		 * of unittests will test this path.  Do not print the stack
 351		 * trace when the error is caused by unittest so that we do
 352		 * not display what a normal developer might reasonably
 353		 * consider a real bug.
 354		 */
 355		if (!IS_ENABLED(CONFIG_OF_UNITTEST) ||
 356		    strcmp(node->parent->full_name, "testcase-data")) {
 357			dump_stack();
 358			pr_err("ERROR: next of_node_put() on this node will result in a kobject warning 'refcount_t: underflow; use-after-free.'\n");
 359		}
 360
 361		return;
 362	}
 363	if (!of_node_check_flag(node, OF_DYNAMIC))
 364		return;
 365
 366	if (of_node_check_flag(node, OF_OVERLAY)) {
 367
 368		if (!of_node_check_flag(node, OF_OVERLAY_FREE_CSET)) {
 369			/* premature refcount of zero, do not free memory */
 370			pr_err("ERROR: memory leak before free overlay changeset,  %pOF\n",
 371			       node);
 372			return;
 373		}
 374
 375		/*
 376		 * If node->properties non-empty then properties were added
 377		 * to this node either by different overlay that has not
 378		 * yet been removed, or by a non-overlay mechanism.
 379		 */
 380		if (node->properties)
 381			pr_err("ERROR: %s(), unexpected properties in %pOF\n",
 382			       __func__, node);
 383	}
 384
 385	if (node->child)
 386		pr_err("ERROR: %s() unexpected children for %pOF/%s\n",
 387			__func__, node->parent, node->full_name);
 388
 389	property_list_free(node->properties);
 390	property_list_free(node->deadprops);
 391	fwnode_links_purge(of_fwnode_handle(node));
 392
 393	kfree(node->full_name);
 394	kfree(node->data);
 395	kfree(node);
 396}
 397
 398/**
 399 * __of_prop_dup - Copy a property dynamically.
 400 * @prop:	Property to copy
 401 * @allocflags:	Allocation flags (typically pass GFP_KERNEL)
 402 *
 403 * Copy a property by dynamically allocating the memory of both the
 404 * property structure and the property name & contents. The property's
 405 * flags have the OF_DYNAMIC bit set so that we can differentiate between
 406 * dynamically allocated properties and not.
 407 *
 408 * Return: The newly allocated property or NULL on out of memory error.
 409 */
 410struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
 411{
 412	struct property *new;
 413
 414	new = kzalloc(sizeof(*new), allocflags);
 415	if (!new)
 416		return NULL;
 417
 418	/*
 419	 * NOTE: There is no check for zero length value.
 420	 * In case of a boolean property, this will allocate a value
 421	 * of zero bytes. We do this to work around the use
 422	 * of of_get_property() calls on boolean values.
 423	 */
 424	new->name = kstrdup(prop->name, allocflags);
 425	new->value = kmemdup(prop->value, prop->length, allocflags);
 426	new->length = prop->length;
 427	if (!new->name || !new->value)
 428		goto err_free;
 429
 430	/* mark the property as dynamic */
 431	of_property_set_flag(new, OF_DYNAMIC);
 432
 433	return new;
 434
 435 err_free:
 436	__of_prop_free(new);
 
 
 437	return NULL;
 438}
 439
 440/**
 441 * __of_node_dup() - Duplicate or create an empty device node dynamically.
 442 * @np:		if not NULL, contains properties to be duplicated in new node
 443 * @full_name:	string value to be duplicated into new node's full_name field
 444 *
 445 * Create a device tree node, optionally duplicating the properties of
 446 * another node.  The node data are dynamically allocated and all the node
 447 * flags have the OF_DYNAMIC & OF_DETACHED bits set.
 448 *
 449 * Return: The newly allocated node or NULL on out of memory error.  Use
 450 * of_node_put() on it when done to free the memory allocated for it.
 451 */
 452struct device_node *__of_node_dup(const struct device_node *np,
 453				  const char *full_name)
 454{
 455	struct device_node *node;
 456
 457	node = kzalloc(sizeof(*node), GFP_KERNEL);
 458	if (!node)
 459		return NULL;
 460	node->full_name = kstrdup(full_name, GFP_KERNEL);
 461	if (!node->full_name) {
 462		kfree(node);
 463		return NULL;
 464	}
 465
 466	of_node_set_flag(node, OF_DYNAMIC);
 467	of_node_set_flag(node, OF_DETACHED);
 468	of_node_init(node);
 469
 470	/* Iterate over and duplicate all properties */
 471	if (np) {
 472		struct property *pp, *new_pp;
 473		for_each_property_of_node(np, pp) {
 474			new_pp = __of_prop_dup(pp, GFP_KERNEL);
 475			if (!new_pp)
 476				goto err_prop;
 477			if (__of_add_property(node, new_pp)) {
 478				__of_prop_free(new_pp);
 
 
 479				goto err_prop;
 480			}
 481		}
 482	}
 483	return node;
 484
 485 err_prop:
 486	of_node_put(node); /* Frees the node and properties */
 487	return NULL;
 488}
 489
 490/**
 491 * of_changeset_create_node - Dynamically create a device node and attach to
 492 * a given changeset.
 493 *
 494 * @ocs: Pointer to changeset
 495 * @parent: Pointer to parent device node
 496 * @full_name: Node full name
 497 *
 498 * Return: Pointer to the created device node or NULL in case of an error.
 499 */
 500struct device_node *of_changeset_create_node(struct of_changeset *ocs,
 501					     struct device_node *parent,
 502					     const char *full_name)
 503{
 504	struct device_node *np;
 505	int ret;
 506
 507	np = __of_node_dup(NULL, full_name);
 508	if (!np)
 509		return NULL;
 510	np->parent = parent;
 511
 512	ret = of_changeset_attach_node(ocs, np);
 513	if (ret) {
 514		of_node_put(np);
 515		return NULL;
 516	}
 517
 518	return np;
 519}
 520EXPORT_SYMBOL(of_changeset_create_node);
 521
 522static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
 523{
 524	if (ce->action == OF_RECONFIG_ATTACH_NODE &&
 525	    of_node_check_flag(ce->np, OF_OVERLAY)) {
 526		if (kref_read(&ce->np->kobj.kref) > 1) {
 527			pr_err("ERROR: memory leak, expected refcount 1 instead of %d, of_node_get()/of_node_put() unbalanced - destroy cset entry: attach overlay node %pOF\n",
 528			       kref_read(&ce->np->kobj.kref), ce->np);
 529		} else {
 530			of_node_set_flag(ce->np, OF_OVERLAY_FREE_CSET);
 531		}
 532	}
 533
 534	of_node_put(ce->np);
 535	list_del(&ce->node);
 536	kfree(ce);
 537}
 538
 539static void __of_changeset_entry_invert(const struct of_changeset_entry *ce,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 540					  struct of_changeset_entry *rce)
 541{
 542	memcpy(rce, ce, sizeof(*rce));
 543
 544	switch (ce->action) {
 545	case OF_RECONFIG_ATTACH_NODE:
 546		rce->action = OF_RECONFIG_DETACH_NODE;
 547		break;
 548	case OF_RECONFIG_DETACH_NODE:
 549		rce->action = OF_RECONFIG_ATTACH_NODE;
 550		break;
 551	case OF_RECONFIG_ADD_PROPERTY:
 552		rce->action = OF_RECONFIG_REMOVE_PROPERTY;
 553		break;
 554	case OF_RECONFIG_REMOVE_PROPERTY:
 555		rce->action = OF_RECONFIG_ADD_PROPERTY;
 556		break;
 557	case OF_RECONFIG_UPDATE_PROPERTY:
 558		rce->old_prop = ce->prop;
 559		rce->prop = ce->old_prop;
 560		/* update was used but original property did not exist */
 561		if (!rce->prop) {
 562			rce->action = OF_RECONFIG_REMOVE_PROPERTY;
 563			rce->prop = ce->prop;
 564		}
 565		break;
 566	}
 567}
 568
 569static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
 570		bool revert)
 571{
 572	struct of_reconfig_data rd;
 573	struct of_changeset_entry ce_inverted;
 574	int ret = 0;
 575
 576	if (revert) {
 577		__of_changeset_entry_invert(ce, &ce_inverted);
 578		ce = &ce_inverted;
 579	}
 580
 581	switch (ce->action) {
 582	case OF_RECONFIG_ATTACH_NODE:
 583	case OF_RECONFIG_DETACH_NODE:
 584		memset(&rd, 0, sizeof(rd));
 585		rd.dn = ce->np;
 586		ret = of_reconfig_notify(ce->action, &rd);
 587		break;
 588	case OF_RECONFIG_ADD_PROPERTY:
 589	case OF_RECONFIG_REMOVE_PROPERTY:
 590	case OF_RECONFIG_UPDATE_PROPERTY:
 591		ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
 592		break;
 593	default:
 594		pr_err("invalid devicetree changeset action: %i\n",
 595			(int)ce->action);
 596		ret = -EINVAL;
 597	}
 598
 599	if (ret)
 600		pr_err("changeset notifier error @%pOF\n", ce->np);
 601	return ret;
 602}
 603
 604static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
 605{
 
 
 606	int ret = 0;
 607
 608	of_changeset_action_debug("apply: ", ce->action, ce->np, ce->prop);
 609
 
 610	switch (ce->action) {
 611	case OF_RECONFIG_ATTACH_NODE:
 612		__of_attach_node(ce->np);
 613		break;
 614	case OF_RECONFIG_DETACH_NODE:
 615		__of_detach_node(ce->np);
 616		break;
 617	case OF_RECONFIG_ADD_PROPERTY:
 
 
 
 
 
 
 
 
 
 618		ret = __of_add_property(ce->np, ce->prop);
 
 
 
 
 
 
 619		break;
 620	case OF_RECONFIG_REMOVE_PROPERTY:
 621		ret = __of_remove_property(ce->np, ce->prop);
 
 
 
 
 
 
 622		break;
 623
 624	case OF_RECONFIG_UPDATE_PROPERTY:
 625		ret = __of_update_property(ce->np, ce->prop, &ce->old_prop);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 626		break;
 627	default:
 628		ret = -EINVAL;
 629	}
 
 630
 631	if (ret) {
 632		of_changeset_action_err("apply failed: ", ce->action, ce->np, ce->prop);
 633		return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 634	}
 635
 636	return 0;
 637}
 638
 639static inline int __of_changeset_entry_revert(const struct of_changeset_entry *ce)
 640{
 641	struct of_changeset_entry ce_inverted;
 642
 643	__of_changeset_entry_invert(ce, &ce_inverted);
 644	return __of_changeset_entry_apply(&ce_inverted);
 645}
 646
 647/**
 648 * of_changeset_init - Initialize a changeset for use
 649 *
 650 * @ocs:	changeset pointer
 651 *
 652 * Initialize a changeset structure
 653 */
 654void of_changeset_init(struct of_changeset *ocs)
 655{
 656	memset(ocs, 0, sizeof(*ocs));
 657	INIT_LIST_HEAD(&ocs->entries);
 658}
 659EXPORT_SYMBOL_GPL(of_changeset_init);
 660
 661/**
 662 * of_changeset_destroy - Destroy a changeset
 663 *
 664 * @ocs:	changeset pointer
 665 *
 666 * Destroys a changeset. Note that if a changeset is applied,
 667 * its changes to the tree cannot be reverted.
 668 */
 669void of_changeset_destroy(struct of_changeset *ocs)
 670{
 671	struct of_changeset_entry *ce, *cen;
 672
 673	/*
 674	 * When a device is deleted, the device links to/from it are also queued
 675	 * for deletion. Until these device links are freed, the devices
 676	 * themselves aren't freed. If the device being deleted is due to an
 677	 * overlay change, this device might be holding a reference to a device
 678	 * node that will be freed. So, wait until all already pending device
 679	 * links are deleted before freeing a device node. This ensures we don't
 680	 * free any device node that has a non-zero reference count.
 681	 */
 682	device_link_wait_removal();
 683
 684	list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
 685		__of_changeset_entry_destroy(ce);
 686}
 687EXPORT_SYMBOL_GPL(of_changeset_destroy);
 688
 689/*
 690 * Apply the changeset entries in @ocs.
 691 * If apply fails, an attempt is made to revert the entries that were
 692 * successfully applied.
 693 *
 694 * If multiple revert errors occur then only the final revert error is reported.
 695 *
 696 * Returns 0 on success, a negative error value in case of an error.
 697 * If a revert error occurs, it is returned in *ret_revert.
 698 */
 699int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
 700{
 701	struct of_changeset_entry *ce;
 702	int ret, ret_tmp;
 703
 704	pr_debug("changeset: applying...\n");
 705	list_for_each_entry(ce, &ocs->entries, node) {
 706		ret = __of_changeset_entry_apply(ce);
 707		if (ret) {
 708			pr_err("Error applying changeset (%d)\n", ret);
 709			list_for_each_entry_continue_reverse(ce, &ocs->entries,
 710							     node) {
 711				ret_tmp = __of_changeset_entry_revert(ce);
 712				if (ret_tmp)
 713					*ret_revert = ret_tmp;
 714			}
 715			return ret;
 716		}
 717	}
 718
 719	return 0;
 720}
 721
 722/*
 723 * Returns 0 on success, a negative error value in case of an error.
 724 *
 725 * If multiple changeset entry notification errors occur then only the
 726 * final notification error is reported.
 727 */
 728int __of_changeset_apply_notify(struct of_changeset *ocs)
 729{
 730	struct of_changeset_entry *ce;
 731	int ret = 0, ret_tmp;
 732
 733	pr_debug("changeset: emitting notifiers.\n");
 734
 735	/* drop the global lock while emitting notifiers */
 736	mutex_unlock(&of_mutex);
 737	list_for_each_entry(ce, &ocs->entries, node) {
 738		ret_tmp = __of_changeset_entry_notify(ce, 0);
 739		if (ret_tmp)
 740			ret = ret_tmp;
 741	}
 742	mutex_lock(&of_mutex);
 743	pr_debug("changeset: notifiers sent.\n");
 744
 745	return ret;
 746}
 747
 748/*
 749 * Returns 0 on success, a negative error value in case of an error.
 750 *
 751 * If a changeset entry apply fails, an attempt is made to revert any
 752 * previous entries in the changeset.  If any of the reverts fails,
 753 * that failure is not reported.  Thus the state of the device tree
 754 * is unknown if an apply error occurs.
 755 */
 756static int __of_changeset_apply(struct of_changeset *ocs)
 757{
 758	int ret, ret_revert = 0;
 759
 760	ret = __of_changeset_apply_entries(ocs, &ret_revert);
 761	if (!ret)
 762		ret = __of_changeset_apply_notify(ocs);
 763
 764	return ret;
 765}
 766
 767/**
 768 * of_changeset_apply - Applies a changeset
 769 *
 770 * @ocs:	changeset pointer
 771 *
 772 * Applies a changeset to the live tree.
 773 * Any side-effects of live tree state changes are applied here on
 774 * success, like creation/destruction of devices and side-effects
 775 * like creation of sysfs properties and directories.
 776 *
 777 * Return: 0 on success, a negative error value in case of an error.
 778 * On error the partially applied effects are reverted.
 779 */
 780int of_changeset_apply(struct of_changeset *ocs)
 781{
 782	int ret;
 783
 784	mutex_lock(&of_mutex);
 785	ret = __of_changeset_apply(ocs);
 786	mutex_unlock(&of_mutex);
 787
 788	return ret;
 789}
 790EXPORT_SYMBOL_GPL(of_changeset_apply);
 791
 792/*
 793 * Revert the changeset entries in @ocs.
 794 * If revert fails, an attempt is made to re-apply the entries that were
 795 * successfully removed.
 796 *
 797 * If multiple re-apply errors occur then only the final apply error is
 798 * reported.
 799 *
 800 * Returns 0 on success, a negative error value in case of an error.
 801 * If an apply error occurs, it is returned in *ret_apply.
 802 */
 803int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
 804{
 805	struct of_changeset_entry *ce;
 806	int ret, ret_tmp;
 807
 808	pr_debug("changeset: reverting...\n");
 809	list_for_each_entry_reverse(ce, &ocs->entries, node) {
 810		ret = __of_changeset_entry_revert(ce);
 811		if (ret) {
 812			pr_err("Error reverting changeset (%d)\n", ret);
 813			list_for_each_entry_continue(ce, &ocs->entries, node) {
 814				ret_tmp = __of_changeset_entry_apply(ce);
 815				if (ret_tmp)
 816					*ret_apply = ret_tmp;
 817			}
 818			return ret;
 819		}
 820	}
 821
 822	return 0;
 823}
 824
 825/*
 826 * If multiple changeset entry notification errors occur then only the
 827 * final notification error is reported.
 828 */
 829int __of_changeset_revert_notify(struct of_changeset *ocs)
 830{
 831	struct of_changeset_entry *ce;
 832	int ret = 0, ret_tmp;
 833
 834	pr_debug("changeset: emitting notifiers.\n");
 835
 836	/* drop the global lock while emitting notifiers */
 837	mutex_unlock(&of_mutex);
 838	list_for_each_entry_reverse(ce, &ocs->entries, node) {
 839		ret_tmp = __of_changeset_entry_notify(ce, 1);
 840		if (ret_tmp)
 841			ret = ret_tmp;
 842	}
 843	mutex_lock(&of_mutex);
 844	pr_debug("changeset: notifiers sent.\n");
 845
 846	return ret;
 847}
 848
 849static int __of_changeset_revert(struct of_changeset *ocs)
 850{
 851	int ret, ret_reply;
 852
 853	ret_reply = 0;
 854	ret = __of_changeset_revert_entries(ocs, &ret_reply);
 855
 856	if (!ret)
 857		ret = __of_changeset_revert_notify(ocs);
 858
 859	return ret;
 860}
 861
 862/**
 863 * of_changeset_revert - Reverts an applied changeset
 864 *
 865 * @ocs:	changeset pointer
 866 *
 867 * Reverts a changeset returning the state of the tree to what it
 868 * was before the application.
 869 * Any side-effects like creation/destruction of devices and
 870 * removal of sysfs properties and directories are applied.
 871 *
 872 * Return: 0 on success, a negative error value in case of an error.
 873 */
 874int of_changeset_revert(struct of_changeset *ocs)
 875{
 876	int ret;
 877
 878	mutex_lock(&of_mutex);
 879	ret = __of_changeset_revert(ocs);
 880	mutex_unlock(&of_mutex);
 881
 882	return ret;
 883}
 884EXPORT_SYMBOL_GPL(of_changeset_revert);
 885
 886/**
 887 * of_changeset_action - Add an action to the tail of the changeset list
 888 *
 889 * @ocs:	changeset pointer
 890 * @action:	action to perform
 891 * @np:		Pointer to device node
 892 * @prop:	Pointer to property
 893 *
 894 * On action being one of:
 895 * + OF_RECONFIG_ATTACH_NODE
 896 * + OF_RECONFIG_DETACH_NODE,
 897 * + OF_RECONFIG_ADD_PROPERTY
 898 * + OF_RECONFIG_REMOVE_PROPERTY,
 899 * + OF_RECONFIG_UPDATE_PROPERTY
 900 *
 901 * Return: 0 on success, a negative error value in case of an error.
 902 */
 903int of_changeset_action(struct of_changeset *ocs, unsigned long action,
 904		struct device_node *np, struct property *prop)
 905{
 906	struct of_changeset_entry *ce;
 907
 908	if (WARN_ON(action >= ARRAY_SIZE(action_names)))
 909		return -EINVAL;
 910
 911	ce = kzalloc(sizeof(*ce), GFP_KERNEL);
 912	if (!ce)
 913		return -ENOMEM;
 914
 915	/* get a reference to the node */
 916	ce->action = action;
 917	ce->np = of_node_get(np);
 918	ce->prop = prop;
 919
 
 
 
 920	/* add it to the list */
 921	list_add_tail(&ce->node, &ocs->entries);
 922	return 0;
 923}
 924EXPORT_SYMBOL_GPL(of_changeset_action);
 925
 926static int of_changeset_add_prop_helper(struct of_changeset *ocs,
 927					struct device_node *np,
 928					const struct property *pp)
 929{
 930	struct property *new_pp;
 931	int ret;
 932
 933	new_pp = __of_prop_dup(pp, GFP_KERNEL);
 934	if (!new_pp)
 935		return -ENOMEM;
 936
 937	ret = of_changeset_add_property(ocs, np, new_pp);
 938	if (ret)
 939		__of_prop_free(new_pp);
 940
 941	return ret;
 942}
 943
 944/**
 945 * of_changeset_add_prop_string - Add a string property to a changeset
 946 *
 947 * @ocs:	changeset pointer
 948 * @np:		device node pointer
 949 * @prop_name:	name of the property to be added
 950 * @str:	pointer to null terminated string
 951 *
 952 * Create a string property and add it to a changeset.
 953 *
 954 * Return: 0 on success, a negative error value in case of an error.
 955 */
 956int of_changeset_add_prop_string(struct of_changeset *ocs,
 957				 struct device_node *np,
 958				 const char *prop_name, const char *str)
 959{
 960	struct property prop;
 961
 962	prop.name = (char *)prop_name;
 963	prop.length = strlen(str) + 1;
 964	prop.value = (void *)str;
 965
 966	return of_changeset_add_prop_helper(ocs, np, &prop);
 967}
 968EXPORT_SYMBOL_GPL(of_changeset_add_prop_string);
 969
 970/**
 971 * of_changeset_add_prop_string_array - Add a string list property to
 972 * a changeset
 973 *
 974 * @ocs:	changeset pointer
 975 * @np:		device node pointer
 976 * @prop_name:	name of the property to be added
 977 * @str_array:	pointer to an array of null terminated strings
 978 * @sz:		number of string array elements
 979 *
 980 * Create a string list property and add it to a changeset.
 981 *
 982 * Return: 0 on success, a negative error value in case of an error.
 983 */
 984int of_changeset_add_prop_string_array(struct of_changeset *ocs,
 985				       struct device_node *np,
 986				       const char *prop_name,
 987				       const char * const *str_array, size_t sz)
 988{
 989	struct property prop;
 990	int i, ret;
 991	char *vp;
 992
 993	prop.name = (char *)prop_name;
 994
 995	prop.length = 0;
 996	for (i = 0; i < sz; i++)
 997		prop.length += strlen(str_array[i]) + 1;
 998
 999	prop.value = kmalloc(prop.length, GFP_KERNEL);
1000	if (!prop.value)
1001		return -ENOMEM;
1002
1003	vp = prop.value;
1004	for (i = 0; i < sz; i++) {
1005		vp += snprintf(vp, (char *)prop.value + prop.length - vp, "%s",
1006			       str_array[i]) + 1;
1007	}
1008	ret = of_changeset_add_prop_helper(ocs, np, &prop);
1009	kfree(prop.value);
1010
1011	return ret;
1012}
1013EXPORT_SYMBOL_GPL(of_changeset_add_prop_string_array);
1014
1015/**
1016 * of_changeset_add_prop_u32_array - Add a property of 32 bit integers
1017 * property to a changeset
1018 *
1019 * @ocs:	changeset pointer
1020 * @np:		device node pointer
1021 * @prop_name:	name of the property to be added
1022 * @array:	pointer to an array of 32 bit integers
1023 * @sz:		number of array elements
1024 *
1025 * Create a property of 32 bit integers and add it to a changeset.
1026 *
1027 * Return: 0 on success, a negative error value in case of an error.
1028 */
1029int of_changeset_add_prop_u32_array(struct of_changeset *ocs,
1030				    struct device_node *np,
1031				    const char *prop_name,
1032				    const u32 *array, size_t sz)
1033{
1034	struct property prop;
1035	__be32 *val __free(kfree) = kcalloc(sz, sizeof(__be32), GFP_KERNEL);
1036	int i;
1037
1038	if (!val)
1039		return -ENOMEM;
1040
1041	for (i = 0; i < sz; i++)
1042		val[i] = cpu_to_be32(array[i]);
1043	prop.name = (char *)prop_name;
1044	prop.length = sizeof(u32) * sz;
1045	prop.value = (void *)val;
1046
1047	return of_changeset_add_prop_helper(ocs, np, &prop);
1048}
1049EXPORT_SYMBOL_GPL(of_changeset_add_prop_u32_array);
1050
1051/**
1052 * of_changeset_add_prop_bool - Add a boolean property (i.e. a property without
1053 * any values) to a changeset.
1054 *
1055 * @ocs:	changeset pointer
1056 * @np:		device node pointer
1057 * @prop_name:	name of the property to be added
1058 *
1059 * Create a boolean property and add it to a changeset.
1060 *
1061 * Return: 0 on success, a negative error value in case of an error.
1062 */
1063int of_changeset_add_prop_bool(struct of_changeset *ocs, struct device_node *np,
1064			       const char *prop_name)
1065{
1066	struct property prop;
1067
1068	prop.name = (char *)prop_name;
1069	prop.length = 0;
1070	prop.value = NULL;
1071
1072	return of_changeset_add_prop_helper(ocs, np, &prop);
1073}
1074EXPORT_SYMBOL_GPL(of_changeset_add_prop_bool);
1075
1076static int of_changeset_update_prop_helper(struct of_changeset *ocs,
1077					   struct device_node *np,
1078					   const struct property *pp)
1079{
1080	struct property *new_pp;
1081	int ret;
1082
1083	new_pp = __of_prop_dup(pp, GFP_KERNEL);
1084	if (!new_pp)
1085		return -ENOMEM;
1086
1087	ret = of_changeset_update_property(ocs, np, new_pp);
1088	if (ret)
1089		__of_prop_free(new_pp);
1090
1091	return ret;
1092}
1093
1094/**
1095 * of_changeset_update_prop_string - Add a string property update to a changeset
1096 *
1097 * @ocs:	changeset pointer
1098 * @np:		device node pointer
1099 * @prop_name:	name of the property to be updated
1100 * @str:	pointer to null terminated string
1101 *
1102 * Create a string property to be updated and add it to a changeset.
1103 *
1104 * Return: 0 on success, a negative error value in case of an error.
1105 */
1106int of_changeset_update_prop_string(struct of_changeset *ocs,
1107				    struct device_node *np,
1108				    const char *prop_name, const char *str)
1109{
1110	struct property prop = {
1111		.name = (char *)prop_name,
1112		.length = strlen(str) + 1,
1113		.value = (void *)str,
1114	};
1115
1116	return of_changeset_update_prop_helper(ocs, np, &prop);
1117}
1118EXPORT_SYMBOL_GPL(of_changeset_update_prop_string);